1. Field of the Invention
The present invention relates to a method of working a band blade that is a so-called Thomson blade.
2. Description of the Prior Art
As shown in FIGS. 18A and 19, a band blade 1 which is a so-called Thomson blade has an sharp blade portion 13 along one edge in the width direction of a strip-like ridge portion 12. The band blade 1 is subjected to necessary workings and then used in, for example, the formation of breaks or a fold in a paper piece, a paper sheet, a wood piece, or the like. In addition to working for folding the band blade 1 into a predetermined shape, workings which may be applied to the band blade 1 include: working of punching given portions of the ridge portion 12 of the band blade 1 into a rectangular shape to form bridges 14 in the ridge portion 12 as shown in FIG. 18B; and that of cutting away the bridges 14 as shown in FIG. 18C. The cutting of the bridges 14 may be conducted by, for example, a so-called miter cutting in which, as shown in the XXA portion in FIG. 18C and in FIG. 20A, the blade portion 13 is obliquely crossly cut so that one cut end 13a has the same inclination angle .theta.2 as the inclination angle .theta.1 (see FIG. 19) of the side face of the blade portion 13, or so-called straight cutting in which, as shown in the XXB portion in FIG. 18C and in FIG. 20B, the blade portion 13 is cut perpendicular to the blade edge so that both cut ends 13c have a straight end face. As shown in FIG. 21, for example, the band blade 1 which has undergone miter cutting so that the blade portion 13 protrudes from the end of the band blade 1 is placed so that the cut end 13a of the blade portion 13 is tightly butted against a side face of a blade portion 13' of another band blade 1' serving as a counter member.
Conventionally, when an end of a band blade on which miter cutting or straight cutting is applied and which is bent into a predetermined shape is to be produced, a long band blade is cut to form a band blade of a constant length, and bending and miter cutting or straight cutting are then applied to the band blade of a constant length. It is approximately considered that this is conducted because of the following reason. In a band-blade working apparatus of the prior art, a bending mechanism is placed in the front part of the feeding path of a band blade, and a band-blade cutting tool and a bridge punching mechanism are placed in the rear of the bending mechanism. In the case where a long band blade is used as it is, after the band blade is once bent by using the bending mechanism, therefore, the band blade cannot be retracted to the rear of the bending mechanism to be cut.